Handling of radio-active sources

ABSTRACT

An isotope capsule carried at the end of a radio-active source holder is handled by retracting the source holder from one position into a curved passage of a guide member through an inlet at one end of the passage, turning the guide member through an angle of less than 360* about the central axis of the other end of the passage, and then ejected through the inlet into a different position. Manipulating apparatus for withdrawing and inserting the radio-active source holder from and to a hole in a shielded transport container for the source holder and for transferring the source holder to and from a location beyond the container comprises a curved tube adapted to receive the source holder and mounted for rotation about the central axis of one of its ends so that the other end can be selectively brought into alignment with the hole in the container or with at least one guide path for the source holder externally of the container, and an operating mechanism for effecting rotation of the curved tube only in response to movement of the source holder through the operating mechanism under the influence of a remotely driven control cable attached to the source holder.

ic'l'ail hvbe I United State;

Ellis HANDLING OF RADIO-ACTIVESOURCES Jack Ellis, London, England SidneyGeoffrey Young, London, England Filed: Apr. 9, 1973 Appl. No.: 348,896

Inventor:

Assignee:

US. Cl. 250/497, 250/506 Int. Cl. G21f 5/00 Field of Search 250/506,507, 505, 515,

Primary ExaminerArchie R. Borchelt Assistant ExaminerDavis L. WillisAttorney, Agent, or Firm-Perry Carvellas, Esq.

[57] ABSTRACT An isotope capsule carried at the end of a radio-active 1Nov. 12, 1974 sagc, turning the guide member through an angle of lessthan 360 about the central axis of the other end of the passage, andthen ejected through the inlet into a different position. Manipulatingapparatus for withdrawing and inserting the radio-active source holderfrom and to a hole in a shielded transport container for the sourceholder and for transferring the source holder to and from a locationbeyond the container comprises a curved tube adapted to receive thesource holder and mounted for rotation about the central axis of one ofits ends so that the other end can be selectively brought into alignmentwith the hole in the container or with at least one guide path for thesource holder externally of the container, and an operating mechanismfor effecting rotation of the curved tube only in response to movementof the source holder through the operating mechanism under the influenceof a remotely driven control cable attached to the source holder.

7 Claims, 11 Drawing Figures PATENTL NOV 1 2 I974 SHEET 10F 6 sum nor a$848813! PATENILL, m 1 21974 PMENTL rqsv I 21974 SHEET 5 OF 6 HANDLINGOF RADIO-ACTIVE SOURCES According to the invention, a method of handlingan isotope capsule carried at the end of a radio-active source holdercomprises retracting the source holder from one position into a curvedpassage of a guide member through an inlet at one end of the passage,turning the guide member through an angle of less than 360 about thecentral axis of the other end of the passage, and then ejecting thesource holder through the inlet into a different position.

The invention also extends to manipulating apparatus for withdrawing andinserting a radio-active source holder from and to a hole in a shieldedtransport container for the source holder and for transferring thesource holder to and from a location beyond the container. Suchapparatus comprises a curved tube adapted to receive the source holderand mounted for rotation about the central axis of one of its ends sothat the other end can be selectively brought into alignment with thehole in the container or with at least one guide path for the sourceholder externally of the container, and an operating mechanism foreffecting rotation of the curved tube only in response to movement ofthe source holder through the operating mechanism under the influence ofa remotely driven control cable attached to the source holder. Thus, ifthe source holder is in a transport container located in one room, itcan be retracted along a predetermined path and into the tube of whichthe inlet is in alignment with the path, and the tube is swung throughan angle of, say, 180 until its inlet is aligned with a second pathleading to a different room, such swinging taking place only when thesource holder has been fully retracted into the tube. The source holderis then ejected along said second path.

The invention will now be described by way of example with reference tothe accompanying drawings, wherein:

FIG. 1 is a diagrammatic representation of a transport container for aradio-active source fitted with a withdrawal and manipulating mechanismfor transferring the source to a point of use;

FIG. 2 is a sectional side elevation of a preferred container andpreferred manipulator;

FIG. 3 is a sectional side elevation of a slightly modifled operatingmechanism of the FIG. 2 manipulator but shown in a different conditionof operation;

FIG. 4 is a cross-section on the line IV-IV in FIG.

FIG. 5 is a diagrammatic perspective view of a component of theoperating mechanism of FIGS. 2 to 4;

F IGS.6 to are diagrammatic representations of the operating mechanismin various conditions for explaining the operating sequence, and

FIG. 11 is a diagram showing a planar projection of a cam track providedin the FIG. 5 component.

Referring firstly to FIG. 1, the diagram shows a shielded combinationtransport and exposure container 1 for a flexible source holder orpencil 2. The preferred container and source pencil are illustrated inmore detail in FIG. 2, although it is to be understood that theinvention is readily applicable to other containers and source holdersor pencils. The source pencil carries an isotope capsule in a receptacleat one end and the entire pencil is shielded in a straight hole 5 in thecontainer 1. Upon arrival of the container with pencil, the

container is adapted for use as a storage and exposure container bybeing fitted with a remotely-controllable manipulator 3 whichincludes acurved tube 4 mounted for rotation about the central axis 6 at one ofits ends.

When the isotope is to be usefully exposed, (a closure cap that was usedto seal the hole 5 during transit and storage having been removed fromthe container and the manipulator 3 having been fitted to thecontainer), the pencil 2 is withdrawn from the container in thedirection of the arrow A in FIG. 1 by being pulled with a cable thatenters the manipulator along the axis 6.

The flexible pencil 2 enters an inlet end 7 of the tube 4 and iswithdrawn until it is entirely disposed in the tube or has even passedbeyond it, this causing the tube to be rotated through about the axis 6so that the end 7 will now be aligned with a guide path 8 for thepencil, along which the pencil is pushed in the direction of arrow B,with the isotope capsule foremost, until it reaches a change-over block9. The latter is rotatable and contains a curved hole which can bebrought into alignment with a selected one of a plurality of guide paths11 by turning the block. Continued pushing in the direction of one ofthe arrows C will then bring the pencil with isotope to the selectedplace of exposure, possibly with the interposition of furtherchange-over blocks and/or tubes similar to the block 9 and tube 4. Afteruse, the pencil 2 is brought to a different location for exposure or itis returned to its container 1 by movement in the direction of thearrows X, Y and Z.

Referring, now,'to FIGS. 2 to 11, one or other of which shows in moredetail the aforementioned container 1, pencil 2, manipulator 3, hole 5,tube 4 with its inlet end 7, and guide path 8 formed by a fixed tube, itshould be mentioned first of all that a connector 12 (FIG. 2) on thecontainer 1 serves, during transport and storage, to attach a screw-oncap (not shown) for closing the hole 5 and shielding the flexible pencil2 which carries the isotope capsule in a receptable 13. When the cap hasbeen removed, the manipulator 3 can be secured to the container by meansof a mounting case 14. The manipulator carries an operating mechanism16, the fixed tube forming the guide path 8. The rotatable tube 4 issecured in a rotary sleeve 17 of the operating mechanism. The connector12 incorporates a lateral locking or safety screw 18 for locking thesource holder or pencil 2 against withdrawal from the container byengaging in a groove 19 of the pencil. The pencil is constructed of aplurality of pivotally interconnected links so that it is flexible andcan assume a curved shape. When the safety screw 18 is disengaged fromthe pencil, it engages instead in a socket 21 of the mounting case 14,thereby serving as a deterrent against the case being removed before thepencil has been locked against withdrawal from the container.

Other provisions are also made for safety reasons. For example, as bestshown in FIG. 2 a roller 22 carried by the mounting case 14 at the endof a springinfluenced arm 20 extends through a slot in the side of thetube 4 and will not permit the pencil 2 to be pulled out of thecontainer until a plate 23 is swung to free the roller by turning aspecial key 24 and until the arm 20 has been depressed. At this time, asignal 26 carried by the arm appears through a window 27 in the case 14to indicate that the pencil is now in a potentially dangerouswithdrawable or withdrawn condition. An eccentric cam disc 28 carried bythe tube 4 of the operating mechanism and adapted to depress the roller22 as the tube is rotated prevents the roller 22 from returning underspring influence to its FIG. 2 blocking position in the tube unless thetube end 7 nearest the container 1 is in alignment with the hole 5 inthe container. This is best seen by comparing FIGS. 6 and (where theroller 22 is blocking withdrawal of the pencil 2 from the container 1)with FIGS. 7 and 8 (where the roller has been depressed but could bereturned to the blocking position) and with-FIG. 9 (where the tube end 7is no longer in alignment with the hole 5 and the cam disc 28, which hasswung through 180 together with the tube 4, prevents the roller 22 fromassuming a blocking position).

The operating mechanism 16 of the manipulator 3 comprises a housing 31in which the aforementioned sleeve 17 that carries the tube 4 is mountedfor rotation by roller bearings (see FIGS. 2 and 3). The housing has anentry fitting 32 for a remotely-driven control cable 33 and it containsa hollow piston 34 through which the cable can pass at one end 36 whichconstitutes an abutment, the other end of the piston being open. Thepiston 34 is concentric with and surrounds the sleeve 17 and it isconstrained to execute limited rectilinear movement in the housing 31 bystationary guide pins 37 of the housing engaging in straight grooves 38of the piston 34 (FIGS. 3 and 4) or of a sleeve 39 carried by the piston(FIG. 2). A spring 41 biasses the piston towards the right-hand side asviewed in FIG. 2 to assume a limiting position in which one end of thepiston strikes a stop in the form of a shoulder 42 provided intermediatethe ends of the sleeve 17 or in which the abutment 36 strikes a stopconstituted by the end of the sleeve 17. Projecting from the piston 34into a cam track 43 in the sleeve 17 there are two spring-influenced camfollower pins 44 (only one is shown in FIG. 2 and might suffice). Thecam track is shown as a planar projection in FIG. 11 and it will benoted that it comprises two straight line portions which are parallel tothe rotary axis of the sleeve 17 interconnected by two helical portions(also see FIG. 5) so that the cam track is closed on itself.

} The arrangement is such that, when the sleeve 17 is in a rotaryposition at which the end 7 of the tube is in alignment with the hole '5and the piston 34 abuts against the sleeve 17 (either with the abutment36 against the end of the sleeve or with the end of the piston againstthe shoulder 42, or both), then the cam follower pins 44 will bedisposed at the respective commencements of the helical portions of thecam track. Referring to FIG. 2, when the cable 33 has been attached tothe pencil 2 and it is desired to withdraw the pencil from the container1, a pull is exerted by the remote drive on the cable, the roller 22having first been unlocked by turning the key 24 to swing away the plate23. The FIG. 2 condition of the operating mechanism and pencil is againreproduced in FIG. 6 diagram which also illustrates a second lockingroller but this second roller is not essential and is not in factincluded in the FIGS. 2 and 3 constructions. As the pencil is beingpulled out of the hole 5 in the direction of the arrow A of FIGS. 1 and7, it rides on and depresses the roller 22 (FIG. 7) and then enters thesleeve 17 through the tube 4 after having depressed the second roller,if this is provided. This condition is shown in FIG. 8 where the end ofthe pencil 2 has already been pulled up against the abutment 36 of thepiston 34 and the pencil is located wholly within the sleeve 17 and tube4.

track 44 in the sleeve, displacement of the piston towards the left inFIG. 2 and in the direction of the arrow M in FIG. 8 from one limitingposition to the other therefore causes the sleeve 17 to rotate as thecam follower pins traverse the cam track. By the time the piston 34 hasstruck the end of the housing, the pins 44 will have traversed theentire respective helical cam track portions and the sleeve 17 will havebeen turned through thereby also having turned the tube 4 (FIGS. 3 and9) to bring its end 7 into alignment with the guide path 8. At this timethe roller 22 is prevented from returning to its undepressed conditionby the cam disc 28 which has been turned together with the tube 4.

The cam follower pins will now be disposed at the commencements of thestraight cam track portions so that, as the pull on the cable 33 isreleased and the spring 41 returns the piston 34 towards the right inFIG. 3, the pins 44 will ride along the straight cam track portionswithout turning the sleeve 17 and the pencil 2 is ejected in thedirection of the arrow B in FIGS. 1 and 9. Continued feeding of thecable 33 by the remotelydriven control will advance the pencil towherever the path 8 may lead, the operating mechanism 16 remainingunaffected, with the pins 44 at the ends of the straight track portionsand the commencements of the helical portions. The next occasion thatthe piston 34 will be displaced occurs on returning the pencil in thedirection of arrows Y (FIG. 1) and N (FIG. 10), when the pencil willagain strike the abutment 36. As before, the sleeve 17 will turn through180, this time to bring the tube end 7 back into alignment with the hole5 and to cause the cam disc 28 to release the roller 22. Upon returnmovement of the piston, the sleeve will not turn and the pencil is fedinto the hole 5, after which the roller 22 will be back in the FIGS. 2and 6 condition and can be locked with the key-actuated plate 23.

It will be evident that the design of the cam track 43 determines thedegree of rotation of the sleeve 17 on each to and fro movement of thepiston and consequently, by altering the number of helical cam trackportions and interconnecting straight line portions, it is readilypossible to feed the pencil from the container into a selected one of aplurality of guide paths 8, as previously described in relation to thepaths 1 l in FIG. 1. Indeed, an operating mechanism similar to the oneshown at 16 could be incorporated with the changeover block 9 in FIG. 1or at any other desired location.

I claim:

1. A method of handling an isotope capsule carried at ttteend.pim mys.ssi eh comprising retracting the source holder from one position intoa curved passage of a guide member through an inlet at one end of thepassage, turning the guide member through an angle of less than 360about the central axis of the other end of the passage, and thenejecting the source holder through the inlet into a different position.

2. Manipulating apparatus for withdrawing and inserting a radio-activesource holder from and to a hole in a shielded transport container forthe source holder and for transferring the source holder to and from alocation beyond the container, comprising a curved tube adapted toreceive the source holder and mounted for rotation about the centralaxis of one of its ends so that the other end can be selectively broughtinto alignment with the hole in the container or with at least one guidepath for the source holder externally of the container, and an operatingmechanism for effecting rotation of the curved tube only in response tomovement of the source holder through the operating mechanism under theinfluence 'of a remotely-driven control cable attached to the sourceholder.

3. Apparatus according to claim 2 including a mounting case securable tothe transport container and carrying the operating mechanism, themounting case including a fixed tube constituting said external guidepath and a socket for receiving a safety screw of the container when thescrew is in a position at which it permits withdrawal of the sourceholder from the hole in the container.

4. Apparatus according to claim 3, wherein the curved tube is providedwith a slot in its side and the mounting case carries a roller which isspringinfluenced to engage through the slot when the said other tube endis aligned with the hole in the container.

5. Apparatus according to claim 4, wherein the mounting case carries akey-operated pivotable plate for locking the roller in its slot-engagingposition.

6. Apparatus according to claim 4, wherein the curved tube carries a camdisc which is fixed for rotation therewith and is adapted to hold theroller out of engagement with the slot unless the said other tube end isaligned with the hole in the container.

7. Apparatus according to claim 2, wherein the operating mechanismcomprises a housing, a sleeve mounted for rotation in the housing, thecurved tube being fixed with its said one end in the sleeve, a hollowpiston which is constrained to execute limited rectilinear displacementin the housing between one end of the housing and a stop on the sleeveand is concentric with and surrounds the sleeve, an abutment on thepiston, the cable being able to pass through the sleeve. abutment andhousing and the source holder being able to enter the piston up to theabutment when pulled through the sleeve by the cable, a spring forbiassing the piston against the stop on the'sleeve, a cam track providedon the sleeve and at least one cam follower pin projecting from thepiston into the cam track, the cam track comprising at least two helicalportions interconnected by straight line portions extending parallel tothe rotary axis of the sleeve so that the cam track is closed on itself,and the arrangement being such that, when the source holder has beenpulled by the cable up to the abutment and the pull is maintained toovercome the bias of the spring, the source holder will displace thepiston from its limiting position against the stop on the sleeve to itslimiting position against the said one end of the housing, during whichtime the sleeve and the curved tube fixed thereto are rotated by the camfollower pin traversing one of the helical cam track portions and, whenthe pull is released, the spring will return the piston to its limitingposition against the stop on the sleeve, during which time the camfollower pin traverses one of the straight line cam track portionswithout causing the sleeve to rotate.

1. A method of handling an isotope capsule carried at the end of aratio-active source holder, comprising retracting the source holder fromone position into a curved passage of a guide member through an inlet atone end of the passage, turning the guide member through an angle ofless than 360* about the central axis of the other end of the passage,and then ejecting the source holder through the inlet into a differentposition.
 2. Manipulating apparatus for withdrawing and inserting aradio-active source holder from and to a hole in a shielded transportcontainer for the source holder and for transferring the source holderto and from a location beyond the container, comprising a curved tubeadapted to receive The source holder and mounted for rotation about thecentral axis of one of its ends so that the other end can be selectivelybrought into alignment with the hole in the container or with at leastone guide path for the source holder externally of the container, and anoperating mechanism for effecting rotation of the curved tube only inresponse to movement of the source holder through the operatingmechanism under the influence of a remotely-driven control cableattached to the source holder.
 3. Apparatus according to claim 2including a mounting case securable to the transport container andcarrying the operating mechanism, the mounting case including a fixedtube constituting said external guide path and a socket for receiving asafety screw of the container when the screw is in a position at whichit permits withdrawal of the source holder from the hole in thecontainer.
 4. Apparatus according to claim 3, wherein the curved tube isprovided with a slot in its side and the mounting case carries a rollerwhich is spring-influenced to engage through the slot when the saidother tube end is aligned with the hole in the container.
 5. Apparatusaccording to claim 4, wherein the mounting case carries a key-operatedpivotable plate for locking the roller in its slot-engaging position. 6.Apparatus according to claim 4, wherein the curved tube carries a camdisc which is fixed for rotation therewith and is adapted to hold theroller out of engagement with the slot unless the said other tube end isaligned with the hole in the container.
 7. Apparatus according to claim2, wherein the operating mechanism comprises a housing, a sleeve mountedfor rotation in the housing, the curved tube being fixed with its saidone end in the sleeve, a hollow piston which is constrained to executelimited rectilinear displacement in the housing between one end of thehousing and a stop on the sleeve and is concentric with and surroundsthe sleeve, an abutment on the piston, the cable being able to passthrough the sleeve, abutment and housing and the source holder beingable to enter the piston up to the abutment when pulled through thesleeve by the cable, a spring for biassing the piston against the stopon the sleeve, a cam track provided on the sleeve and at least one camfollower pin projecting from the piston into the cam track, the camtrack comprising at least two helical portions interconnected bystraight line portions extending parallel to the rotary axis of thesleeve so that the cam track is closed on itself, and the arrangementbeing such that, when the source holder has been pulled by the cable upto the abutment and the pull is maintained to overcome the bias of thespring, the source holder will displace the piston from its limitingposition against the stop on the sleeve to its limiting position againstthe said one end of the housing, during which time the sleeve and thecurved tube fixed thereto are rotated by the cam follower pin traversingone of the helical cam track portions and, when the pull is released,the spring will return the piston to its limiting position against thestop on the sleeve, during which time the cam follower pin traverses oneof the straight line cam track portions without causing the sleeve torotate.